Age resisting vulcanized rubber and antioxidant agent



Patented July 25, 1933 UNITED STATES PATENT OFFICE HAROLD A. MORTON, OF AKRON, OHIO AGE RESISTING VULCANIZED RUBBER AND ANTIOXIDANT AGENT No Drawing.

My invention relates to rubber or rubberlike compounds and more particularly to those having incorporated therein or applied thereto, an anti-oxidant, whereby the aging quality of the compound is materially enhanced. e

I have discovered that certain diamino substituted ethyl ethers, Wheninoorporated in a rubber or rubber-like compound prior to the 0 vulcanization'thereof, or when applied to a vulcanized article, materially retard deterioration due to oxidation.

There are a great number of such diamino substituted ethyl ethers which function in this manner and in general they may be represented by the following general chemical constitution:

In the above representation of the constituwtional formula, the chemical radicals attached to the nitrogen atoms are denoted by the 'symbo'ls R(a), 11 2) R(0).and R(d and may be any-of the following chemical groups or their equivalents:

It may be prepared by heating four mols of aniline (372 pounds) with one mol of BB dichlor ethyl ether (1&3 pounds) at a 'temperature of about 200 C. until reaction is complete. The reaction product is then eX- tracted with a large quantity of hot water which eliminates the aniline hydrochloride,

and leaves the semi-purified product as a residue. The yield in general is about .200

Application filed July 25, 1930. Serial No. 470,775.

pounds and approximately one-half of the aniline employed, may be recovered from the aniline hydrochloride solution. The semipurified product also contains N -phenyl morpholine and small quantities of other materials.

In order to carry out the invention, the semi-purified product may be utilized, as such or it may be further purified.

While, in the above example, I have given the preferred method of manufacture,'it is v also possible to obtain products valuable as age resisters by using different ratios of BB dichlor ethyl ether and aniline. In other words, it is possible to use only two or three mols of aniline per mol of BB dichlor ethyl ether and it is also possible to use lower temperatures of reaction.

In this specification, Where BB diamino substituted ethyl ethers are referred to, it is intended to denote the reaction product of BB dichlor ethyl ether with amines. The conventional chemical formula of. BB dichlor ethyl ether is: H

After the removal of the amine-hydrochloride, this semi-purified productmay be used, in many cases without further pu-rification. Or, if desired, the reaction product may be further purified. While it'i's-con sid'ered that the above reaction takes place inthe manner indicated, I do not wishto be bound by anyof the chemical theories herein containe'd but desire to loo-protected by Letters Patent on the product obtained by heating'BBdichlor I ethyl ether with amines and by the product obtained I mean the semi-purified product containing several ingredients or the purified product from which some ofthe by-products, such as morpholine derivatives havej-been removed.

Other typical anti-oxidants belongingto this class'and prepared in the manner above indicated, are as follows? -i BB (11 (ortho tolylaminoyethyl-pther BE di (para tolyl amino) ethyl ether BB (ll (Xylyl amino) ethyl ether BB'oi (alpha naphthyLamino) etl 1 other BB di (beta n'aphthyl amino) ethy ether BB (li (ethyl phenyl amino) ethyl ether B (phenyl amino) B (ortho tolyl amino) ethyl ether B (phenyl amino) B (para tolyl amino) ethyl ether B (phenyl amino) 8' (alpha naphtliyl amino) ethyl ether BB diamino ethyl ether BB di (methyl amino) ethyletlier B (phenyl amino). B amino ethyl ether B (plienyl amino) B (methyl amino) ethyl ether (pheuyl amino) B (butyl amino) ethyl ether (phenyl amino) B (ethyl amino) ethyl ether B di (ethyl amino) ethyl ether (ortho tolyl amino) B amino ethyl ether (ortho tolyl am 10) B (methyl amino) ethyl ether (ortho tolyl am l5 (ethyl amino) ethyl ether (para tolyl no,- B' amino ethyl ether (para tolyl amino) B (methyl amino) ethyl ether (para tolyl amino) B (ethyl amino) ethyl ether (xylyl amino) B (phenyl amino) ethyl ether (xylyl amino) B (ortho tolyl amino) ethyl ether (Xylyl amino) B (ethyl phenyl amino) ethyl ether (xylyl amino) B amino ethyl ether (Xylyl amino) B (methyl amino) ethyl ether B (oi-tho tolyl amino) B (alpha naphthyl amino) ethyl ether B (ortho tolyl amino) B (para tolyl amino) ethyl ether 8 (phenyl amino) B (ethyl phenyl amino) ethyl ether B (para tolyl amino) B (ethyl phenyl amino) ethyl ether There are many other materials of this class which function as anti-oxidants and the above list of materials serves only to indicate the scope of the invention.

l/Vhile the materials cited above are the free bases it is also possible to use certain soaps and salts of these materials without materially affecting the anti-oxidant value.

In general, the most beneficial elISClZ is obtained by using 0.75% to 1.5% of the antioxidant agent in the rubber compound (based on the rubber content) but lesser or greater quantities may be used, depending on purpose at hand. In general,and up to a certain point, the durability of the rubber goods is a function of the quantity of the material employed.

The materials listed above possess little or no accelerating properties and may be introduccd directly into the rubber stock without materially disturbing the factory rate of cure. Those which have slight accelerating properties, either alone or in conjunction with the accelerator employed .in the stock, may be added directly to the rubber stock and the accelerator content adjusted so that the rate of cure remains the same.

It has also been found possible to add the material after the rubber stock has been vulcanized and still obtain appreciable improvement in the aging qualities of the stock. This may be done by painting. or dipping the rubber stock with a solution of the desired ma terial and after allowing penetration to take place, to dry oil? the surplus solvent.

As examples of carrying out the invention the following are typical. In all of the examples tensile means tensile strength at break in pounds per square inch; elongation represents elongation at break in percent and cure is given in minutes at steam pressure per square inch.

E acample 1 The composition of the rubber stock is as follows:

Two stocks were mixed, one according to the recipe and the other the same except for the addition of 1.5% of anti-oxidant.

A ftcr milling and curing, the two rubber stocus were tested for aging qualities by the usual oven and oxygen bomb methods. I

The results are as follows:

Stocl-:A St0ekB (Without anti- (1.5% antioxidant) oxidant) Days in oven at C. if

'leu- Elon- Ten- Elonslle gation sile gatiou Cure 50 by 401',

Example 2 In this example the use of BB di (Xylyl am no) ethyl other is illustrated. The matcrial was prepared heating 1 mol BB5 then removed and this purified material used as such.

The composition of the rubber stock as follows:

Rubber 55.35 Stearic acid 2.00 Carbon black 0.00 Oil 5.00 Sulphur c 2.25 Zinc oxide 15.00 Diphcnyl guanidine. we- 0.40

Two stocks were mixed, one according to the recipe *as given and the other containing 1.25% anti-oxidant.

The two compounds were milled and calenand subjected to the usual artificial age tests, namely, the oven and oxygen bomb methods.

The results on aging are given in the following table:

dered into sheets th inch in thickness. 70

After vulcanization, the two rubber sheets StookA Stock--B were tested for aging qualitles by the usual gg gfi 33%;? oven and oxygen bomb methods. Days in oven at 70 0.

The results are as follows: E1011 a- Elon 1o Tensile g Tensile g 75 Stock A- Stock B- Without anti- 1.25% anti- Cure 50 by oxidant oxidant D 170C 323 Z23 3333 $3 rays in nvena 1. E1011. Elon- 5 Tensile Tensile 2740 640 3480 640 gatmn 2200 580 3120 010 80 as a a a s Cure by oxyg en bomb 48hrs. by O.by

Original 3220 700 3000 700 3505 000 3020 070 2740 040 3520 000 2260 580 3235 050 1030 540 3100 020 1350 430 2560 500 ggg 230 230 1445 500 2 510 45 Cure 10' by 40# 470 253 33%?) $3 3540 2670 580 3500 010 Cure 90 by a: a2 a 1665 30 21 days 005 340 2500 540 32% g 2 g Oxygen bomb 48 hrs. by 70 C. by 2640 2 2, 9 3001115 275 240 1455 500 1880 470 2820 Z 21d 3313 53 3 $33 a s u 0 1 Cum 90 by Oxyg n bomb 48 hrs. by 70 C.

5 2640 ggg Example .4 1880 3 21 d 218 In this example the use of several BB d1 3 S v s A 1 oxygznbomb tfl hrs. by70C.by (aryl ammo) ethyl ethers is demonstrated.

3001115 300 220 1100 400 They are aq follows. 40

(a) BB d1 (ethyl phenyl amino) ethyl Example? ether prepared by heatmg 1 mol of BB dichlor ethyl ether with 4 mols of ethyl ani- 1 l i a a In Order to demmlstlate 5 1, i l1ne, separating the ethyl aniline. hydrochlo- 45 P ph y fl m etylyl 1 1e 0 rule and removing the morpholine derivativev lowing example is given. The material was The material is then ready for P p y hfillatlng 1 mol 01 BB dlfhlm probable formula for the material is: ethyl ether With 4 mols alpha naphthyl C H C H amine, separating the alpha naphthyl amine 5 hydrochloride and removing the inorphollne 50 derivatiwes. The material was then ready (6) BB di (para tolyl amino) ethyl ether for use. prepared by heating 1 mol of BB dichlor The composition of the rubber stock 1s as thyl th r with 4 11101 f ara toluidi and follows: separating the para toluidine hydrochloride.

55 Rubber 5535 The crude product 1s then ready foi use. q O 0 (0) BB d1 (ortho tolvl amino) ethyl ether r tearic ac1 m0 C b M k prepared by heat1n 1 mol of BB dichlor ar on -ac 20.00 h

r ethyl ether with 4 mols of ortho toluidlne O1 0.00 Zinc Oxide 15 0O separating the ortho toluldine hydrochlonde 1 h W and removmg the morphohne derivative. 60 p ur The material is then read for use The D1pheny1guan1d1ne 0.40 y

probable formula 1s:

100 CH C H NHCH *CH O Two rubber compounds, one with and one GH2 -CH2 NHCH4CH3 55 without anti-oxidant were nuxed and cured (d) BB (phenyl ammo) (alpha naphthyl amino) ethyl ether prepared by heating 1 mol of BB dichlor ethyl ether with 2 mols of aniline and 2 mols of alpha naphthyl amine, and separating the aniline and alpha naphtliyl amine hydrochloride. The crude product is then ready for use.

To demonstrate the above materials as antioxidants they were mixed into a rubber compound containing the following ingredients:

Rubber 55.35 Stearic acid 2.00 Carbon black 20.00 Oil 5.00 Zinc oxide 15.00 Sulphur 2.25 Diphenyl guanidine 0.40

After vulcanization, the rubber stocks were subjected to artificial age tests. The results are given in the following table. In the following table, Elong means elongation at break in percent.

Withont anti-oxi- 1.25%A 1.25%B- 1.25%41- 1.2591D dant Da sinOvenat ,9. 2 3 2 m o. a a a aa 5'. 2 3 2 E 2 E. 2 8 2 B Ffl B H E F 1 E H B B1 Cure 50 by 40%;

3820 700 4370 700 3680 670 3735 710 3890 720 3565 660 3570 640 3605 650 3880 680 4100 690 2740 640 3105 650 3600 670 3540 690 3755 700 2260 580 2560 620 3440 660 2995 670 3580 650 1930 640 2520 580 3240 050 3120 640 3225 660 1350 430 1950 490 2900 610 2465 590 2845 550 Oxygen bomb 48 hrs. by C. by 300 lbs 230 230 710 420 2%!0 640 1440 570 2000 (H0 Cure 70 by 40# 680 3680 620 4045 680 4020 670 000 3600 590 4020 660 4010 650 600 3440 600 3465 030 3700 650 560 3315 590 3090 000 3495 610 510 3120 570 3040 590 3185 590 400 2820 530 2580 540 2710 510 Oxygen bomb 48 hrs. by 70 C. by 300 lbs 270 240 825 400 2305 600 1395 500 1910 570 Cure 90 by 40# Original 3580 630 4045 660 3580 600 4120 050 3930 630 580 3800 580 3660 590 4015 630 550 3340 580 3280 590 3530 570 500 3155 520 3065 540 3220 550 440 3065 530 2880 510 2830 500 y 340 2710 480 2360 450 2420 420 Oxygen bomb 48 hrs. by 70 C. by 300 lbs 300 230 650 340 2020 520 1400 460 1885 500 What I claim is 1. A rubber composition including a BB diamino diethyl ether wherein one of the hydrogen atoms of each amino group is replaced by an alkyl hydrocarbon residue.

2. A rubber composition including a BB diamino diethyl ether wherein one of the hydrogen atoms of one amino group is replaced 5. A rubber composition including the product obtained by heating one mol of BB dichlor diethyl ether with at least two mols of a secondary aromatic amine.

6. A rubber composition including the product, from which morpholine derivatives have been removed, obtained by heating one mol of BB dichlor diethyl ether with at least two mol s of a secondary aromatic amine.

HAROLD A. MORTON. 

